首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4883478篇
  免费   370656篇
  国内免费   14712篇
耳鼻咽喉   68671篇
儿科学   157186篇
妇产科学   129785篇
基础医学   734929篇
口腔科学   138001篇
临床医学   446999篇
内科学   887996篇
皮肤病学   118733篇
神经病学   401354篇
特种医学   187471篇
外国民族医学   754篇
外科学   734440篇
综合类   135050篇
现状与发展   24篇
一般理论   2851篇
预防医学   415560篇
眼科学   115240篇
药学   342582篇
  31篇
中国医学   12644篇
肿瘤学   238545篇
  2021年   58021篇
  2019年   60304篇
  2018年   77144篇
  2017年   58871篇
  2016年   65077篇
  2015年   77966篇
  2014年   113085篇
  2013年   178663篇
  2012年   143705篇
  2011年   153116篇
  2010年   132801篇
  2009年   131967篇
  2008年   137360篇
  2007年   147656篇
  2006年   154251篇
  2005年   149012篇
  2004年   148072篇
  2003年   137712篇
  2002年   126503篇
  2001年   178469篇
  2000年   174352篇
  1999年   158698篇
  1998年   73561篇
  1997年   68788篇
  1996年   67136篇
  1995年   62313篇
  1994年   56540篇
  1993年   52525篇
  1992年   116520篇
  1991年   113051篇
  1990年   108974篇
  1989年   106352篇
  1988年   98249篇
  1987年   96366篇
  1986年   91230篇
  1985年   89227篇
  1984年   73320篇
  1983年   65325篇
  1982年   50240篇
  1981年   46794篇
  1980年   43932篇
  1979年   65470篇
  1978年   52183篇
  1977年   45475篇
  1976年   42569篇
  1975年   43667篇
  1974年   48971篇
  1973年   47133篇
  1972年   44441篇
  1971年   41436篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
14.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
15.
16.
17.
18.

Background

Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.

Methods

PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.

Results

Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.

Conclusions

MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.
  相似文献   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号